Groundwater resources are gaining much attention with increasing demands for water due to increasing population, urbanization and agricultural expansion in Egypt. First objective of this paper is to interpret Vertical Electrical Soundings (VES) in a number of stations covering Assiut Governorate to assess the geometry of the Quaternary aquifer (QA). The VES interpretation covered the determination of depth, thickness and true resistivity of the geoelectrical layers and then picking the water bearing layer (aquifer). The VES interpretation reflects the outstanding role of QA variation in the studied area. Second objective is to use open-hole logging data from 52 wells for determining the detailed reservoir characteristics to evaluate the hydrogeologic and petrophysical parameters of the aquifer. The well log analysis procedures are performed in different phases led to formation evaluation using specially designed program utilizing the level by level technique.  Accordingly, the QA petrophysical parameters including the total, effective porosity, shale content, permeability, lithology, Bulk Volume Water (BVW), water salinity and net pay presented in the form of litho-saturation cross-plots and distribution maps. Such parameters are useful in case of subjecting the area to modeling or GIS studies. Correlation of results indicates that the QA thickness decreases gradually towards the fringes. Total porosity values vary from 23.77% to 39.76%, and the effective one from 21.16% to 38.46%. The calculated permeability values reflect high quality of the studied aquifer. Furthermore, the estimated low shale volumes (4.48 to 25.88%) and high sand volumes (45.59% to 65.62%) of the water-bearing horizons confirmed the good quality of the aquifer. Total dissolved solids (TDS) are in the range from about 400 to 1000 ppm, which indicate fresh type of groundwater.